优化pdf 加载逻辑

src/views/common/DocumentSearch.vue

@@ -73,7 +73,7 @@ if (resolvedWorkerSrc) {
     pdfjsLib.GlobalWorkerOptions.workerSrc = null
 }
 
-const DEFAULT_SCALE = 1.1
+const DEFAULT_SCALE = 1
 const DEFAULT_PDF_URL = 'http://192.168.0.14:9090/smart-bid/technicalSolutionDatabase/2025/10/30/fe5b46ea37554516a71e7c0c486d3715.pdf'
 
 export default {
@@ -268,6 +268,16 @@ export default {
             this.isPrefetching = false
             this.initialPreloadedCount = 0
 
+            // 预先获取第一页的 viewport，用于设置所有容器的初始尺寸
+            let defaultViewport = null
+            try {
+                const firstPage = await this.pdfDoc.getPage(1)
+                defaultViewport = firstPage.getViewport({ scale: this.scale })
+                this.pageCache.set(1, firstPage)
+            } catch (error) {
+                console.warn('获取第一页 viewport 失败', error)
+            }
+
             const fragment = document.createDocumentFragment()
             for (let pageNumber = 1; pageNumber <= this.totalPages; pageNumber += 1) {
                 const placeholder = document.createElement('div')
@@ -276,10 +286,24 @@ export default {
                 placeholder.style.position = 'relative';
                 placeholder.dataset.page = pageNumber
                 placeholder.dataset.status = 'placeholder'
+                
+                // 如果获取到了默认 viewport，预先设置容器尺寸，避免滚动时修改
+                if (defaultViewport) {
+                    placeholder.style.width = `${defaultViewport.width}px`
+                    placeholder.style.height = `${defaultViewport.height}px`
+                    placeholder.style.backgroundColor = '#fff'
+                }
+                
                 fragment.appendChild(placeholder)
                 this.pageContainers.push(placeholder)
             }
             container.appendChild(fragment)
+            
+            // 设置 wrapper 的最小宽度
+            if (defaultViewport && this.$refs.pdfWrapper) {
+                this.$refs.pdfWrapper.style.minWidth = `${Math.ceil(defaultViewport.width)}px`
+            }
+            
             container.scrollTop = 0
 
             this.setupIntersectionObserver()
@@ -289,11 +313,17 @@ export default {
             this.isDocumentReady = true
         },
 
-        ensureContainerDimensions(pageNumber, viewport) {
+        ensureContainerDimensions(pageNumber, viewport, force = false) {
             const index = pageNumber - 1
             const container = this.pageContainers[index]
             if (!container) return
 
+            // 如果容器已经有尺寸且不是强制更新，则跳过，避免滚动时修改尺寸导致滚动位置跳动
+            const hasDimensions = container.style.width && container.style.height && container.style.width !== '0px' && container.style.height !== '0px'
+            if (hasDimensions && !force && container.dataset.status !== 'placeholder') {
+                return
+            }
+
             container.style.width = `${viewport.width}px`
             container.style.height = `${viewport.height}px`
             container.style.margin = '0px auto 10px'
@@ -330,7 +360,8 @@ export default {
             if (!container) return null
 
             const viewport = page.getViewport({ scale: this.scale })
-            this.ensureContainerDimensions(pageNumber, viewport)
+            // 渲染时允许更新尺寸（如果 viewport 与预设不同）
+            this.ensureContainerDimensions(pageNumber, viewport, true)
             container.classList.add('is-loading')
 
             const oldCanvas = container.querySelector('.pdf-canvas')
@@ -497,8 +528,8 @@ export default {
                     try {
                         const page = await this.pdfDoc.getPage(pageNumber)
                         this.pageCache.set(pageNumber, page)
-                        const viewport = page.getViewport({ scale: this.scale })
-                        this.ensureContainerDimensions(pageNumber, viewport)
+                        // 预取时只缓存页面对象，不修改容器尺寸，避免滚动时影响滚动位置
+                        // 容器尺寸会在实际渲染时通过 ensureContainerDimensions 设置
                     } catch (error) {
                         console.warn(`预取第 ${pageNumber} 页失败`, error)
                     }